Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Total Capital Commitments, Unfunded Capital Commitments, and Our Ownership in Each Fund (Additional Information) (Detail) - Venture capital and private equity fund investments - Investment	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Other fund investments
Venture Capital and Private Equity Fund Investments [Line Items]
Number of other funds with investment commitments	255
Other fund investments | Upper Limit
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	5.00%
Fair value accounting | Other private equity fund
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	0.00%	58.20%
Fair value accounting | Direct ownership interest | SVB Capital Partners II, LP
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	1.30%
Fair value accounting | Indirect ownership interest | SVB Capital Partners II, LP
Venture Capital and Private Equity Fund Investments [Line Items]
Percentage of ownership	3.80%